Update on the so. Arizona fireball – June 23

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Reports continue to come in from all over southern and central Arizona of Tuesday evening’s fireball. The most interesting reports involve a series of loud sonic booms heard from Tucson southward. Most of the sonic boom reports are from the Sierra Vista to Green Valley area.

I would like to thanks everyone who has submitted reports. It is greatly appreciated and will help us understand this event better. Also remember to file a report with the American Meteor Society at http://www.amsmeteors.org/fireball/report.html .

I was hoping to find more video of the fireball especially from amateur all-sky fireball cameras. There are 3 such cameras in the area but all were down for maintenance and testing during the time. And yes that is partially my fault. Oh, well, next time… An additional camera near El Paso would have seen it but was clouded out.

Luckily, there is an all-sky camera that runs all day and night on Mount Hopkins, where the 6.5-m MMT telescope resides. This camera is used by the astronomers to check sky conditions during their observing runs. It is usually used to watch for clouds and fog. But it is also great at picking up other things such as meteors and satellites. [Note: all of the movies taken by this camera are archived on line and can be seen by the public at http://skycam.mmto.arizona.edu/ .

The camera takes a series of ~10 second exposures. Tuesday’s fireball was picked up on 2 consecutive images. The 1st image below shows the early stages of the fireball. At this point the fireball is bright but probably not much brighter than Venus. Note the time is 9:21 pm.

Single frame from MMT skycam. Thanks to Tim Pickering for giving permission to post this image and Rich Kowalski for making the snapshot.

The 2nd frame is completely washed out. During the 2nd half of the fireball’s flight, its brightness rivaled the Full Moon. This easily overwhelmed the camera since its len iris was wide open for night-time observing.

Single frame from MMT skycam. Thanks to Tim Pickering for giving permission to post this image and Rich Kowalski for making the snapshot.

The single MMT sky cam image does provide some great information on where the fireball came from and its path. Combing this image with my own naked eye observations, I was able to map out a preliminary path over southern Arizona. The map below (made with Google Earth) combines the MMT sky cam observations of the 1st few seconds of the fireball with my observations of the last few seconds.

Note: This is my first time doing this so the path could be completely wrong. For all of you meteorite hunters out there, don’t completely trust this path. Then again, if it helps you find some pieces, I want one. 🙂

The first detection (by the sky cam) occurs over the border to the east of Nogales at an altitude of 70-80 km. The sky cam is limited to bright objects, so naked eye observers may have been able to see it even earlier. My last observation occurs between Benson and Huachuca City at an altitude of ~20-30 km. The “heartbeat” symbols are reports of sonic booms. These reports cluster nicely near the middle to end of the path when the fireball was breaking up and should have produced sonic booms.

Possible path of the June 23 fireball over so. Arizona. "Heartbeat" symbols denote sonic boom reports. Made with Google Earth.

So what was this? It was most likely a small asteroid hitting the atmosphere at ~20 km per seconds (12 miles per second). Originally the asteroid was probably not much bigger than a basketball. Again by combining the data from above, the fireball originated from the direction of the constellation of Corvus (that would be its radiant). There is a very poorly observed meteor shower called the Corvids that may be active right now. It is possible that this fireball is a member of this shower but it is more likely that it was just a Sporadic (meaning it was not associated with any shower).

So the fireball was caused by a small lonely asteroid that just happened to be at the wrong place at the wrong time. Or the right place and time for those lucky enough to have seen it.

3 Comments

I saw a fireball from my apartment balcony in Santiago, Chile on the same night. It was an overcast night, and to suddenly see by far the brightest and longest trail I have ever seen was extremely surprising. I also believe that I possibly saw the object break-up. The break-up appeared like a wet match head sizzling after being struck.

I found a brief news article on what I saw:

Space fireballs sighted from jetliner
A Chilean jetliner flying to New Zealand came “uncomfortably close” to being hit by blazing objects hurtling through the atmosphere, New Zealand aviation officials said Thursday.

The Arizona and Chilean fireballs are 2 different events. In general fireballs are only observed over a distance of hundreds of kilometers. Still it must have been an active night.

Thanks for sharing the MSNBC article. It is notoriously difficult to determine the distance to a fireball or any kind of meteor. You often hear of eyewitnesses saying a fireball was real close, just above the tree tops or down the street,
when it was actually 50 km away. I wouldn’t be surprised if it was much further away from the plane. Plus most
fireballs stop glowing at altitudes of 20-30 km. That well above the altitude of aircraft.

last night close to 2:30 am i was sitting outside with my mom, since we like to star gaze and the sky was more clear than i have ever seen it. straight ahead we saw one of these fireballs, you could see the trail of fire it left behind and the distance.. lets saw it went from one end of a normal 2 car garage house to the other.. since thats how we saw it above our front neighbors house. we didnt hear any sonic boom though.. and ive seen a meteor shower, this thing was huge! and we also saw dozens and dozens of shooting stars so it might as well be a lone meteor. hey now that im on the subject, has anyone seen that star which is wayyy to big to be a star, like imagine a normal big star in the sky and multiply it by 6. its extremely bright and doesn’t flicker colors like a star, kinda like a miniature moon. its been in the night sky for about a month now.. i thought it was maybe mars but mars would be long gone by now. im in maricopa, az and i see it everynight and i cant find anything on it!